Commercial soft feel coatings have been used as industrial coatings in the automotive, computer hardware and printing industries to cover inexpensive plastic parts to give them a pleasing soft feel. These conventional soft feel coatings are generally made from multi-component soft polyurethane resins. The liquid components, generally two or more, are mixed together prior to their application on to the surfaces to cross-link, typically with heat, to form a film on the surfaces. Without cross-linking of the components, the coatings would have poor durability such as scrubability, burnishing resistance, and inferior water resistance and water staining resistance.
Heretofore, commercial soft feel coatings have been somewhat limited to industrial coatings, but have not been widely used in the architectural coatings, such as paints, primers and stains for buildings and dwellings. Architectural coatings are general one-pack, i.e., no mixing is required prior to application of the coating to walls or floors, and architectural coatings are dried or cross-linked at ambient conditions.
The patent literature contains a number of related coating references, CN 1 605 608 (Abstract) discloses colorful suede paint comprising acrylic copolymer emulsion with spherical color polyurethane powder. GB 2 362 387 discloses an aqueous multi-polymer dispersion comprising a soft acrylic polymer (Tg from −70° C. to 19° C.), a hard acrylic polymer (Tg from 40° C. to 115° C.) and polyurethane particles having a weight average diameter (Dw) from 20 nm (or 20×10−9 m) to 200 nm. U.S. Pat. No. 6,835,772 discloses a low temperature curing, soft feel coating composition comprising a polyester or polyester resins (Tg from −30° C. to −70° C.) and lanolin-deposited polyurethane fine particles or clay particles (5 to 40 microns).
U.S. Pat. No. 8,900,669 discloses a clear matte coating having a first polymer (Tg from −60° C. to 100° C.) of 10% to 65% wt., a second particulate (0.5 to 30 μm, Tg from −60° C. to 150° C.) of 10% to 80% wt., and 0.1% to 15% wt. of aminosilane. The first polymer can be acrylic or urethane among other polymers, and the second particulates can be acrylic. U.S. Pat. No. 7,829,626 discloses another an aqueous matte coating having a binder component and a polymeric “duller” component. The duller component can be multi-stage or single stage cross-linked acrylic particles with diameter of 1-20 μm. Preferably, the duller particles are acrylic, vinyl, rubber or urethane (Tg from −60° C. to 75 C). The binder component can be acrylic, vinyl, polyurethane or siloxane having Mw from 200,000 to 10,000,000 for leather and paper applications and Mw of from 10,000 up to 1,000,000 and Tg from 20° C. to 70° C. for architectural coatings.
WO 2013/123357 discloses an aqueous dispersion comprising polyurethane particles (resin) and pigments partially or fully encapsulated with a soft polymer (acrylic, styrene-acrylic or vinyl acrylic with Tg<35° C.). KR 2008 0008522 discloses a coating composition with 10-25% wt. of polyurethane resin, 20-25% wt. of polyethylene resin and 5-7% of acrylic beads (5-8 microns).
In many of these patent references, the small particles or particulates in the aqueous compositions are matting or dulling agents, used to reduce the gloss or sheen of the coating. The small particulates can also be silica as discussed in Petrova et al, “Investigation of Coating Prepared from Polymer with Low Glass Transition Temperature,” Paper No. 52, Advances in Coatings Technology, Nov. 25-27, 2008, Warsaw, Poland.
There remains a need for durable architectural coatings that don't require mixing prior to application on a substrate with good mechanical properties that exhibit soft feel and light diffusion properties.